When the secret plans to a disintegrator gun are stolen by what appears to
have been some kind of giant robot, the newly-regenerated Doctor is
quickly called in to investigate. The trail leads to a group of right-wing
scientists at the Thinktank facility, who are seeking to use the robot and
the disintegrator gun to impose their edicts on humanity. As the situation
escalates, Sarah Jane may prove to be the Doctor's only means of
influencing the robot.

Production

As Doctor Who's eleventh production block neared its conclusion in
1974, the programme was in a state of flux. Although Planet Of The Spiders was to mark the end of
Jon Pertwee's tenure as the Doctor and form the final serial of Season
Eleven, the recording block would continue with the Fourth Doctor's
introductory adventure, which would be held over to start the programme's
twelfth season in the autumn. Outgoing script editor Terrance Dicks, who
was concluding his work on Doctor Who with the Pertwee swansong,
saw this as an opportunity to quickly secure a contract now that he had
returned to the ranks of freelance writing. Dicks convinced his
replacement, Robert Holmes, that the programme had a tradition of
departing script editors being commissioned by their successors, and so he
was assigned the task of writing Serial 4A. (Dicks was formally contracted
much later, on May 23rd.)

At this stage, the new Doctor had yet to be cast, but Dicks and producer
Barry Letts -- who would himself be leaving Doctor Who at the end
of the recording block -- were seriously contemplating casting an elderly
actor in the role. They decided that this would necessitate the
introduction of a new character who would be able to handle the physical
aspects of the storylines, in the vein of Sixties companions such as Ian
Chesterton and Jamie McCrimmon. Letts and Dicks therefore created a UNIT
surgeon named Lieutenant Harry Sullivan (after possibly considering the
surname Sweetman) to accompany the Doctor. Although UNIT was being
gradually deemphasised, it was felt that Harry would also provide an
enduring link to the organisation, thereby adding a familiar element to
the new Doctor's adventures.

With Tom Baker cast as the Doctor rather than an elderly
actor, Harry was made somewhat redundant

To play Harry, Letts cast Ian Marter. Marter boasted a hefty resume of
stage appearances, as well as roles in television series such as The
Brothers and Play For Today. Marter had already appeared in
Doctor Who as John Andrews in Carnival Of
Monsters more than a year before, and had been Letts' initial
choice to play the recurring role of UNIT Captain Mike Yates. Marter and
Elisabeth Sladen were both issued 26-episode contracts on April 16th --
even though by this point, the “elderly Doctor” concept had
been discarded and Tom Baker cast in the lead role, making Harry somewhat
redundant.

Work on the character of the Fourth Doctor proceeded in earnest throughout
the month of March. Joining the team by this point was Doctor Who's
incoming producer, Philip Hinchcliffe. Hinchcliffe had gotten his start in
television as a script editor for ATV, and eventually attained the
position of associate producer on programmes such as General
Hospital, Crossroads, and various children's shows. It was
ultimately agreed that Baker would play the Doctor as more of an eccentric
than Pertwee's prototypical man of action, playing up the fact that, as an
alien, the Doctor's thought processes and reactions could sometimes be a
departure from the human norm.

Drawing upon the bohemian tendencies suggested by both Baker and Letts for
the Fourth Doctor, costume designer James Acheson put together an outfit
which unconsciously echoed the 1892 Aristide Bruant lithographs of
Henri de Toulouse-Lautrec. To knit the scarf he intended the Doctor to
wear (one of the elements inspired by Toulouse-Lautrec), Acheson
approached an elderly woman named Begonia Pope. Misunderstanding Acheson's
instructions, Pope used all the wool given to her, resulting in an
inordinately long scarf. Baker, however, liked the image this conveyed,
and although its length was reduced slightly, it was felt that the scarf
could be incorporated into the action and make an effective prop.

Dicks, meanwhile, had been working on his scripts in consultation with
Holmes. The new script editor was interested in a story which considered
how an advanced, autonomous computer intelligence might behave, while
Dicks was interested in writing about a sympathetic monster, inspired by
the 1933 film King Kong. Dicks also drew heavily on The
Mauritius Penny, an episode of The Avengers he had cowritten
with Malcolm Hulke, most notably for the scenes in which Sarah Jane
infiltrates the meeting of the Scientific Reform Society. Calling the
adventure Robot, Dicks incorporated several hallmarks of the
Pertwee era to reassure audience members. These included the roadster
Bessie and the characters of Brigadier Lethbridge Stewart and Benton (now
promoted to Warrant Officer so that he could replace Captain Yates as the
Brigadier's second-in-command); Nicholas Courtney and John Levene were
issued contracts for Robot on April 17th.

Terrance Dicks reassured viewers by incorporating several
hallmarks of the Jon Pertwee era

The director assigned to Robot was Christopher Barry, whose last
Doctor Who work had been on The Mutants two years before.
Unusually, Barry elected to conduct all location recording using videotape
rather than the traditional film, due to the heavy use of the Colour
Separation Overlay technique required to achieve the effect of the
“giant” robot in episode four. All exterior shooting was
conducted at the BBC Engineering & Training Centre at Wood Norton,
Hereford and Worcester, from April 28th to May 2nd, and from the 5th to
the 6th. Barry was frustrated on the last day by Letts' insistence that he
achieve the Robot's attack on the tank by having a foreground Action Man
toy vanish via roll-back-and-mix -- an effect which proved highly
unsuccessful. Barry had also reserved May 7th as a spare day in case his
schedule was upset due to industrial action by the BBC's scene shifters,
but this does not appear to have been utilised.

Recording was then intended to begin with a two-day session on Tuesday,
May 21st and Wednesday the 22nd in BBC Television Centre Studio 3,
covering all the material from the first two episodes. However, the scene
shifters' labour dispute caused the cancellation of the first recording
day, and limited the shots Barry could accomplish on the second. He ended
up taping scenes set in the vault, the Thinktank workshop, and
Kettlewell's lab on the 22nd -- although due to the strike, a stepladder
which had been left on the latter set had to remain in place, forcing
Barry to shoot around it. The industrial action also meant that the
Doctor Who sets could not be struck after recording had wrapped,
and the next day's episode of Blue Peter had to be taped on them as
a result.

Fortunately, Letts was able to reschedule the entire studio session for
Saturday, June 1st and Sunday the 2nd, again in TC3. Most of the scenes
attempted on the 22nd were remounted; part one was recorded on the first
day alongside the first five scenes of part two, while the rest of that
installment was taped on the second day, in addition to the opening scene
of part three. The concluding studio session then went ahead as scheduled,
on Thursday the 6th (for the remainder of part three and episode four
material set in the control room and the corridor) and Friday the 7th (for
the outstanding segments of part four) in TC3. Letts and Barry became
unhappy with some of the CSO sequences involving the Robot during editing,
however. A remount was finally scheduled for October 24th in TC7, with
Elisabeth Sladen and Michael Kilgarriff reprising some of the scenes
featuring Sarah and the Robot.

Robot was Barry Letts' final
credit as producer of Doctor Who

The conclusion of work on Robot brought Doctor Who's
eleventh recording block to an end, and saw Barry Letts earn his final
credit as the programme's producer, although he continued to supervise
Hinchcliffe for the first two serials of the next group of episodes.
After leaving Doctor Who, Letts continued to produce and direct,
with much of his work concentrating on classics serials for BBC1
(sometimes in concert with Dicks). These included an adaptation of Arthur
Conan Doyle's The Hound Of The Baskervilles, starring Tom Baker as
Sherlock Holmes. Letts would also return to Doctor Who as both a
director (on The Android Invasion) and an
executive producer (supervising novice producer John Nathan-Turner during
Season Eighteen). In the Nineties, he scripted The Paradise Of
Death and The Ghosts Of N-Space, two Doctor Who radio
dramas starring Jon Pertwee. Letts later novelised these stories for
Virgin Publishing. He also contributed two Third Doctor adventures to BBC
Books' line of Doctor Who novels: Deadly Reunion (cowritten
with Dicks) and Island Of Death. Letts passed away on October
9th, 2009 after a battle with cancer.

Hinchcliffe, meanwhile, had decided to save money by avoiding a complete
redesign of the Doctor Who title sequence and logo. These had just
been revamped the year before, and so he instead asked Bernard Lodge to
make only minor changes them, replacing Pertwee's profile with Baker's and
incorporating an image of the TARDIS. This amended sequence heralded the
start of Season Twelve and the Tom Baker era of Doctor Who on
December 28th. The 8.4 million viewers who tuned in could scarcely have
realised that they were witnessing the start of the transformation of
Doctor Who from British television stalwart to worldwide cult
phenomenon...